Effects of electrode assay insertions on the microcirculation of the cochlear lateral wall in vivo

Introduction Preservation of residual hearing is a challenge during cochlear implantation. Cochlear blood flow and microvascular permeability of the cochlear lateral wall microvasculature are possibly affected during electrode array insertions thus deteriorating the maintenance of the endocochlear potential.

Objective Aim of this study was to measure microvascular disturbances in the cochlear lateral wall after experimental cochlear implantations.

Material & methods Normal hearing guinea pigs were randomized and received experimental cochlear implant array insertions (n=8) or sham cochleostomies without insertion (n=8), respectively. Hearing thresholds were monitored using compound action potential measurements. An osseous window was realized in the cochlear lateral wall enabling direct microscopic access to the stria vascularis microcirculation in vivo after intravenous bolus injections of fluorescent markers.

Results Hearing thresholds increased only after electrode insertions. In contrast to the sham controls (+0.8 ±3.6 %baseline) experimental cochlear implantations resulted in significantly reduced cochlear blood flow values (-17.3±3.6 %baseline). Interestingly, at the same time microvascular permeability increased in the cochlear lateral wall after electrode array insertion (+15.5±23.3 %baseline).

Conclusion These findings open new vistas for perioperative drug delivery of novel substances targeting the inner ear.

Diese Studie wurde von der DFG gefördert (STR 1014). Elektrodenträger wurden dankenswerterweise von MED-EL zur Verfügung gestellt.

Poster-PDF A-1590.PDF

Publication History

Article published online:
10 June 2020